TTI scheduling for improved ramp up of TCP throughput in cellular networks

ABSTRACT

A wireless device, such as a user equipment device (UE), and a base station are disclosed, which may communicate with more efficient use of dynamic transmit time interval durations to enable a faster and more efficient ramp up of TCP communications to a higher or maximum throughput. The UE may communicate uplink or downlink communications with the base station according to a first shorter TTI duration for a first period of time. After the first period of time, the UE may communicate uplink or downlink communications to the base station according to a second longer TTI duration. For the case of uplink communications, the UE may be configured to increase a congestion window size after each acknowledgement of an uplink communication received by the base station during the first period of time. For the case of downlink communications, the base station may be configured to increase a congestion window size after each acknowledgement of a downlink communication received by the UE during the first period of time.

PRIORITY CLAIM

This application claims benefit of priority to Application No.62/339,533 titled “TTI Scheduling for Improved Ramp Up of TCP Throughputin Cellular Networks”, filed on May 20, 2016, which is herebyincorporated by reference as though fully and completely set forthherein.

FIELD

The present application relates to wireless devices, and moreparticularly to a method for improved performance in an enhancedcellular network, such as a 5G network.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage. Inparticular, cellular networks are being used by a number of differencedevices and for a number of different services. Newer cellular networkscurrently under development may be asked to support various advancedservices, such as enhanced mobile broadband (eMBB), massive machine typecommunications (MTC), and critical machine applications such asautonomous cars and similar use cases. Improvements in the field wouldbe desirable.

SUMMARY

Embodiments are presented herein of methods for configuring andperforming cellular communication, and of devices configured toimplement the methods. According to the techniques described herein, awireless device such as a user equipment device (UE) may communicatewith a base station according to a radio access technology. The UE andthe base station may communicate with a more efficient usage of dynamictransmit time interval durations to enable a faster and more efficientramp up of TCP communications to a higher or maximum throughput.

In some embodiments, the UE may comprise a radio comprising one or moreantennas configured for wireless communication on a cellular network,and a processing element operably coupled to the radio. The UE may beconfigured to transmit uplink communications to the base stationaccording to a first shorter TTI duration for a first period of time,wherein the UE is configured to increase a congestion window size aftereach acknowledgement of an uplink communication received by the basestation during the first period of time, wherein increasing thecongestion window size enables a corresponding increase in uplink datathroughput. After the first period of time, the UE may be configured totransmit uplink communications to the base station according to a secondlonger TTI duration.

In some embodiments, the UE may be configured to receive downlinkcommunications from the base station according to a first shorter TTIduration for a first period of time. In these embodiments, after thefirst period of time, the UE may be configured to receive downlinkcommunications from the base station according to a second longer TTIduration, wherein receipt of the downlink communications from the basestation according to the first shorter TTI duration for the first periodof time allows the base station to increase a congestion window morerapidly, thereby enabling transmission control protocol (TCP)communications from the base station to ramp up to higher speeds morequickly than if the second longer TTI duration was used during the firstperiod of time.

In some embodiments, the transmission of the uplink communications tothe base station according to the first shorter TTI duration for thefirst period of time allows transmission control protocol (TCP)communications to ramp up to higher speeds more quickly than if thesecond longer TTI duration was used during the first period of time.

In some embodiments, transmission of the uplink communications to thebase station according to the first shorter TTI duration for the firstperiod of time allows the UE to increase the congestion window morerapidly, thereby enabling transmission control protocol (TCP)communications to ramp up to higher speeds more quickly than if thesecond longer TTI duration was used during the first period of time.

In some embodiments, transmission of the uplink communications to thebase station according to the first shorter TTI duration during thefirst period of time results in a shorter round-trip time (RTT) than ifthe second longer TTI duration was used during the first period of time.In these embodiments, the UE may be further configured to increase atransmission rate after each uplink communication RTT.

In some embodiments, the first period of time may end in response todetection of a packet loss in the uplink communications. In otherembodiments, the first period of time may end in response to a slowstart threshold being reached.

In some embodiments, the congestion window size may be used by the UE toavoid transmitting a greater amount of data than can be handled by thenetwork. In these embodiments, UE may be further configured to set thecongestion window size initially to a small multiple of a maximumsegment size (MSS) allowed on a connection between the UE and the basestation, wherein increasing the congestion window size after eachacknowledgement of an uplink communication received by the base stationcomprises increasing the congestion window size after each round triptime.

The techniques described herein may be implemented in and/or used with anumber of different types of devices, including but not limited tocellular phones, tablet computers, wearable computing devices, portablemedia players, and any of various other computing devices.

This summary is intended to provide a brief overview of some of thesubject matter described in this document. Accordingly, it will beappreciated that the above-described features are merely examples andshould not be construed to narrow the scope or spirit of the subjectmatter described herein in any way. Other features, aspects, andadvantages of the subject matter described herein will become apparentfrom the following Detailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present subject matter can be obtainedwhen the following detailed description of the embodiments is consideredin conjunction with the following drawings, in which:

FIG. 1 illustrates an exemplary (and simplified) wireless communicationsystem;

FIG. 2 illustrates a base station (BS) in communication with a userequipment (UE) device;

FIG. 3 illustrates an example wireless cellular communication network,according to some embodiments;

FIG. 4 illustrates an exemplary block diagram of a UE;

FIG. 5 illustrates an exemplary block diagram of a BS;

FIG. 6 illustrates an example frame structure for a 5G cellular RAT;

FIG. 7 is a chart illustrating a faster ramp up of a TCP congestionwindow, and hence a faster increase of communication throughput,according to at least some embodiments described herein;

FIG. 8 illustrates a cellular system architecture for performing uplinkTCP sessions according to some embodiments; and

FIG. 9 illustrates a cellular system architecture for performingdownlink TCP sessions according to some embodiments.

While the features described herein may be susceptible to variousmodifications and alternative forms, specific embodiments thereof areshown by way of example in the drawings and are herein described indetail. It should be understood, however, that the drawings and detaileddescription thereto are not intended to be limiting to the particularform disclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the subject matter as defined by the appended claims.

DETAILED DESCRIPTION

Acronyms

The following acronyms may be used in the present disclosure.

3GPP: Third Generation Partnership Project

3GPP2: Third Generation Partnership Project 2

BLER: Block Error Rate (same as Packet Error Rate)

BER: Bit Error Rate

CC: Component Carrier

CE: Control Element

DL: Downlink

eMBB: enhanced Mobile Broadband

GBR: Guaranteed Bit Rate

GSM: Global System for Mobile Communications

LTE: Long Term Evolution

MAC: Media Access Control

MME: Mobility Management Entity

MTC: Machine Type Communications

PER: Packet Error Rate

RACH: Random Access Channel

RAT: Radio Access Technology

Rx: Receive

RSRP: Reference Signal Received Power

RSRQ: Reference Signal Received Quality

RRC: Radio Resource Control

TCP: Transmit Control Protocol

Tx: Transmission

TTI: Transmit Time Interval

UE: User Equipment

UL: Uplink

UMTS: Universal Mobile Telecommunication System

VoLTE: Voice Over LTE

Terms

The following is a glossary of terms used in this disclosure:

Memory Medium—Any of various types of non-transitory memory devices orstorage devices. The term “memory medium” is intended to include aninstallation medium, e.g., a CD-ROM, floppy disks, or tape device; acomputer system memory or random access memory such as DRAM, DDR RAM,SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash,magnetic media, e.g., a hard drive, or optical storage; registers, orother similar types of memory elements, etc. The memory medium mayinclude other types of non-transitory memory as well or combinationsthereof. In addition, the memory medium may be located in a firstcomputer system in which the programs are executed, or may be located ina second different computer system which connects to the first computersystem over a network, such as the Internet. In the latter instance, thesecond computer system may provide program instructions to the firstcomputer for execution. The term “memory medium” may include two or morememory mediums which may reside in different locations, e.g., indifferent computer systems that are connected over a network. The memorymedium may store program instructions (e.g., embodied as computerprograms) that may be executed by one or more processors.

Carrier Medium—a memory medium as described above, as well as a physicaltransmission medium, such as a bus, network, and/or other physicaltransmission medium that conveys signals such as electrical,electromagnetic, or digital signals.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor that executes instructionsfrom a memory medium.

User Equipment (UE) (or “UE Device”)—any of various types of computersystems devices which are mobile or portable and which performs wirelesscommunications. Examples of UE devices include mobile telephones orsmart phones (e.g., iPhone™, Android™-based phones), portable gamingdevices (e.g., Nintendo DS™ PlayStation Portable™, Gameboy Advance™,iPhone™), wearable devices (e.g., smart watch, smart glasses), laptops,PDAs, portable Internet devices, music players, data storage devices, orother handheld devices, etc. In general, the term “UE” or “UE device”can be broadly defined to encompass any electronic, computing, and/ortelecommunications device (or combination of devices) which is easilytransported by a user and capable of wireless communication.

Base Station—The term “Base Station” has the full breadth of itsordinary meaning, and at least includes a wireless communication stationinstalled at a fixed location and used to communicate as part of awireless telephone system or radio system.

Processing Element—refers to various elements or combinations ofelements. Processing elements include, for example, circuits such as anASIC (Application Specific Integrated Circuit), portions or circuits ofindividual processor cores, entire processor cores, individualprocessors, programmable hardware devices such as a field programmablegate array (FPGA), and/or larger portions of systems that includemultiple processors.

Channel—a medium used to convey information from a sender (transmitter)to a receiver. It should be noted that since characteristics of the term“channel” may differ according to different wireless protocols, the term“channel” as used herein may be considered as being used in a mannerthat is consistent with the standard of the type of device withreference to which the term is used. In some standards, channel widthsmay be variable (e.g., depending on device capability, band conditions,etc.). For example, LTE may support scalable channel bandwidths from 1.4MHz to 20 MHz. In contrast, WLAN channels may be 22 MHz wide whileBluetooth channels may be 1 Mhz wide. Other protocols and standards mayinclude different definitions of channels. Furthermore, some standardsmay define and use multiple types of channels, e.g., different channelsfor uplink or downlink and/or different channels for different uses suchas data, control information, etc.

Automatically—refers to an action or operation performed by a computersystem (e.g., software executed by the computer system) or device (e.g.,circuitry, programmable hardware elements, ASICs, etc.), without userinput directly specifying or performing the action or operation. Thusthe term “automatically” is in contrast to an operation being manuallyperformed or specified by the user, where the user provides input todirectly perform the operation. An automatic procedure may be initiatedby input provided by the user, but the subsequent actions that areperformed “automatically” are not specified by the user, i.e., are notperformed “manually”, where the user specifies each action to perform.For example, a user filling out an electronic form by selecting eachfield and providing input specifying information (e.g., by typinginformation, selecting check boxes, radio selections, etc.) is fillingout the form manually, even though the computer system must update theform in response to the user actions. The form may be automaticallyfilled out by the computer system where the computer system (e.g.,software executing on the computer system) analyzes the fields of theform and fills in the form without any user input specifying the answersto the fields. As indicated above, the user may invoke the automaticfilling of the form, but is not involved in the actual filling of theform (e.g., the user is not manually specifying answers to fields butrather they are being automatically completed). The presentspecification provides various examples of operations beingautomatically performed in response to actions the user has taken.

FIGS. 1 and 2—Communication System

FIG. 1 illustrates an exemplary (and simplified) wireless communicationsystem. It is noted that the system of FIG. 1 is merely one example of apossible system, and embodiments of the invention may be implemented inany of various systems, as desired.

As shown, the exemplary wireless communication system includes a basestation 102A which communicates over a transmission medium with one ormore user devices 106A, 102B, etc., through 106N. Each of the userdevices may be referred to herein as a “user equipment” (UE). Thus, theuser devices 106 are referred to as UEs or UE devices.

The base station 102A may be a base transceiver station (BTS) or cellsite, and may include hardware that enables wireless communication withthe UEs 106A through 106N. The base station 102A may also be equipped tocommunicate with a network 100 (e.g., a core network of a cellularservice provider, a telecommunication network such as a public switchedtelephone network (PSTN), and/or the Internet, among variouspossibilities). Thus, the base station 102A may facilitate communicationbetween the user devices and/or between the user devices and the network100.

The communication area (or coverage area) of the base station may bereferred to as a “cell.” The base station 102A and the UEs 106 may beconfigured to communicate over the transmission medium using any ofvarious radio access technologies (RATs), also referred to as wirelesscommunication technologies, or telecommunication standards, such as GSM,UMTS (WCDMA, TD-SCDMA), LTE, LTE-Advanced (LTE-A), 3GPP2 CDMA2000 (e.g.,1×RTT, 1×EV-DO, HRPD, eHRPD), Wi-Fi, WiMAX etc.

Base station 102A and other similar base stations (such as base stations102B . . . 102N) operating according to the same or a different cellularcommunication standard may thus be provided as a network of cells, whichmay provide continuous or nearly continuous overlapping service to UEs106A-N and similar devices over a wide geographic area via one or morecellular communication standards.

Thus, while base station 102A may act as a “serving cell” for UEs 106A-Nas illustrated in FIG. 1, each UE 106 may also be capable of receivingsignals from (and possibly within communication range of) one or moreother cells (which might be provided by base stations 102B-N and/or anyother base stations), which may be referred to as “neighboring cells”.Such cells may also be capable of facilitating communication betweenuser devices and/or between user devices and the network 100. Such cellsmay include “macro” cells, “micro” cells, “pico” cells, and/or cellswhich provide any of various other granularities of service area size.For example, base stations 102A-B illustrated in FIG. 1 might be macrocells, while base station 102N might be a micro cell. Otherconfigurations are also possible.

In addition to “infrastructure mode” communication in which UEs 106communicate with each other and other networks/devices indirectly by wayof base stations 102, some UEs may also be capable of communicating in a“peer-to-peer” (P2P) or “device-to-device” (D2D) mode of communication.In such a mode, UEs 106 such as UE 106A and UE 106B may communicatedirectly with each other (e.g., instead of by way of an intermediatedevice such as base station 102A). For example, LTE D2D, Bluetooth(“BT”, including BT low energy (“BLE”), Alternate MAC/PHY (“AMP”),and/or other BT versions or features), Wi-Fi ad-hoc/peer-to-peer, and/orany other peer-to-peer wireless communication protocol may be used tofacilitate direct communications between two UEs 106.

Note that a UE 106 may be capable of communicating using any of multipleradio access technologies (RATs) or wireless communication protocols,and may be able to communicate according to multiple wirelesscommunication standards. For example, a UE 106 might be configured tocommunicate using two or more of GSM, UMTS, CDMA2000, WiMAX, LTE, LTE-A,WLAN, Bluetooth, one or more global navigational satellite systems(GNSS, e.g., GPS or GLONASS), one and/or more mobile televisionbroadcasting standards (e.g., ATSC-M/H or DVB-H), etc. Othercombinations of wireless communication standards (including more thantwo wireless communication standards) are also possible.

FIG. 2 illustrates user equipment 106 (e.g., one of the devices 106Athrough 106N) in communication with a base station 102 (e.g., one of thebase stations 102A through 102N). The UE 106 may be a device withcellular communication capability such as a mobile phone, a hand-helddevice, a computer or a tablet, or virtually any type of wirelessdevice.

The UE 106 may include a processor that is configured to execute programinstructions stored in memory. The UE 106 may perform any of the methodembodiments described herein by executing such stored instructions.Alternatively, or in addition, the UE 106 may include a programmablehardware element such as an FPGA (field-programmable gate array) that isconfigured to perform any of the method embodiments described herein, orany portion of any of the method embodiments described herein.

The UE 106 may include one or more antennas for communicating using oneor more wireless communication protocols. In some embodiments, the UE106 may share one or more parts of a receive and/or transmit chainbetween multiple wireless communication standards. The shared radio mayinclude a single antenna, or may include multiple antennas (e.g., forMIMO) for performing wireless communications. Alternatively, the UE 106may include separate transmit and/or receive chains (e.g., includingseparate antennas and other radio components) for each wirelesscommunication protocol with which it is configured to communicate. As afurther alternative, the UE 106 may include one or more radios which areshared between multiple wireless communication protocols, and one ormore radios which are used exclusively by a single wirelesscommunication protocol. Other configurations are also possible.

FIG. 3—Cellular Network

FIG. 3 illustrates an exemplary, simplified portion of a wirelesscommunication system in an LTE network. Note that references to LTEherein may include present and/or future versions of LTE, for exampleincluding LTE-A.

As shown, the wireless device 106 may be in communication with a basestation, shown in this exemplary embodiment as an eNodeB 102. Forexample, the wireless device 106 may utilize an evolved UMTS terrestrialradio access (E-UTRA) air interface to communicate with the eNodeB 102.

In turn, the eNodeB may be coupled to a core network, shown in thisexemplary embodiment as an evolved packet core (EPC) 100. As shown, theEPC 100 may include mobility management entity (MME) 222, homesubscriber server (HSS) 224, and serving gateway (SGW) 226. The EPC 100may include various other devices and/or entities known to those skilledin the art as well.

The term “network” as used herein may refer to one or more of the basestation 102, the MME 222, the HSS 224, the SGW 226 or other cellularnetwork devices not shown. An operation described as being performed by“the network” may performed by one or more of the base station 102, theMME 222, the HSS 224, the SGW 226 or other cellular network devices notshown.

FIG. 4—Exemplary Block Diagram of a UE

FIG. 4 illustrates an exemplary block diagram of a UE 106. As shown, theUE 106 may include a system on chip (SOC) 300, which may includeportions for various purposes. For example, as shown, the SOC 300 mayinclude processor(s) 302 which may execute program instructions for theUE 106 and display circuitry 304 which may perform graphics processingand provide display signals to the display 360. The processor(s) 302 mayalso be coupled to memory management unit (MMU) 340, which may beconfigured to receive addresses from the processor(s) 302 and translatethose addresses to locations in memory (e.g., memory 306, read onlymemory (ROM) 350, Flash memory 310) and/or to other circuits or devices,such as the display circuitry 304, wireless communication circuitry orradio 330, connector I/F 320, and/or display 360. The MMU 340 may beconfigured to perform memory protection and page table translation orset up. In some embodiments, the MMU 340 may be included as a portion ofthe processor(s) 302.

As shown, the SOC 300 may be coupled to various other circuits of the UE106. For example, the UE 106 may include various types of memory (e.g.,including Flash 310), a connector interface 320 (e.g., for coupling to acomputer system, dock, charging station, etc.), the display 360, andwireless communication circuitry (e.g., radio) 330 (e.g., for LTE,Wi-Fi, GPS, etc.).

The UE device 106 may include at least one antenna 335, and in someembodiments multiple antennas, for performing wireless communicationwith base stations and/or other devices. For example, the UE device 106may use antenna 335 to perform the wireless communication. As notedabove, the UE may be configured to communicate wirelessly using multiplewireless communication standards in some embodiments.

As described further, the UE 106 and/or the base station 102 may includehardware and software components for implementing features or methodsdescribed herein in conjunction with cellular communication. Forexample, the base station 102 and the UE 106 may operate to communicateusing cross layer scheduling as described herein.

The processor 302 of the UE device 106 may be configured to implementpart or all of the methods described herein, e.g., by executing programinstructions stored on a memory medium (e.g., a non-transitorycomputer-readable memory medium). In other embodiments, processor 302may be configured as a programmable hardware element, such as an FPGA(Field Programmable Gate Array), or as an ASIC (Application SpecificIntegrated Circuit). Alternatively (or in addition), the processor 302of the UE device 106, in conjunction with one or more of the othercomponents 300, 304, 306, 310, 320, 330, 335, 340, 350, 360 may beconfigured to implement part or all of the features described herein

FIG. 5—Exemplary Block Diagram of a Base Station

FIG. 5 illustrates an exemplary block diagram of a base station 102. Itis noted that the base station of FIG. 5 is merely one example of apossible base station. As shown, the base station 102 may includeprocessor(s) 404 which may execute program instructions for the basestation 102. The processor(s) 404 may also be coupled to memorymanagement unit (MMU) 440, which may be configured to receive addressesfrom the processor(s) 404 and translate those addresses to locations inmemory (e.g., memory 460 and read only memory (ROM) 450) or to othercircuits or devices.

The base station 102 may include at least one network port 470. Thenetwork port 470 may be configured to couple to a telephone network andprovide a plurality of devices, such as UE devices 106, access to thetelephone network as described above in FIGS. 1 and 2.

The network port 470 (or an additional network port) may also oralternatively be configured to couple to a cellular network, e.g., acore network of a cellular service provider. The core network mayprovide mobility related services and/or other services to a pluralityof devices, such as UE devices 106. In some cases, the network port 470may couple to a telephone network via the core network, and/or the corenetwork may provide a telephone network (e.g., among other UE devicesserviced by the cellular service provider).

The base station 102 may include at least one antenna 434, and possiblymultiple antennas. The at least one antenna 434 may be configured tooperate as a wireless transceiver and may be further configured tocommunicate with UE devices 106 via radio 430. The antenna 434communicates with the radio 430 via communication chain 432.Communication chain 432 may be a receive chain, a transmit chain orboth. The radio 430 may be configured to communicate via variouswireless telecommunication standards, including, but not limited to,LTE, LTE-A, UMTS, CDMA2000, etc.

As described further, the BS 102, as well as various of the networkdevices in FIG. 3 or otherwise not shown, may include hardware andsoftware components for implementing features such as those describedherein. The processor 404 of the base station 102 may be configured toimplement part or all of the methods described herein, e.g., byexecuting program instructions stored on a memory medium (e.g., anon-transitory computer-readable memory medium). Alternatively, theprocessor 404 may be configured as a programmable hardware element, suchas an FPGA (Field Programmable Gate Array), or as an ASIC (ApplicationSpecific Integrated Circuit), or a combination thereof. Alternatively(or in addition), the processor 404 of the BS 102, in conjunction withone or more of the other components 430, 432, 434, 440, 450, 460, 470may be configured to implement part or all of the features describedherein.

Problem Summary

The new 5G network technology, currently in development, is expected toprovide new capabilities for UEs, such as higher throughput in themultiple Gbps range. In some embodiments as described in relatedapplication No. 62/339,486 titled “Dynamic Frame Structure for anEnhanced Cellular Network”, 5G may provide a flexible TTI notion thatallows the physical layer to dynamically support different TTI (transmittime interval) sizes ranging from 1 OFDM symbol up to 10 ms. The TCPprotocol is expected to remain one of the most used protocols toestablish and carry traffic data between two users over the Internet.Devices operating in a 5G network may support TCP with largertransmission and reception windows, enabling a larger maximumthroughput. An important problem to solve for a UE in a 5G network ishow to allow the UE throughput to ramp up to the maximum sustainablethroughput as fast and efficiently as possible, without introducingcongestion into the network or adding additional overhead to the databeing transmitted.

Methods detailed in the present disclosure propose a slow-start,cross-layer mechanism for ramping up throughput in a UE device operatingunder 5G technology. Some embodiments described herein relate to crosslayer mechanism between TCP and Layer1/Layer2 to improve the round triptime (RTT) and reduce the overhead based in the TCP window state.

Enhanced Cellular Standards (5G)

Current cellular networks are based on the Long Term Evolution (LTE)network, which was an advance over prior 3G technologies. However, theLTE network has some areas that can be improved. For example, currentcellular networks face a shortage of spectrum, being limited to 100 MHz.Newer radio access technologies (RATs), such as the 5G network standardcurrently in development, should preferably be flexible and scalable tosupport a greater number of frequency bands, from 400 MHz to 100 GHz.

Newer RATs should also offer improved service flexibility. 4G networksintroduced and supported only mobile broadband (MBB), whereas newer 5Gnetworks should be sufficiently flexible to support more advancedservices, such as enhanced mobile broadband (eMBB), massive machine typecommunications (MTC), which may have both low power and very highdensity requirements, and critical machine applications such asautonomous cars and similar use cases which require high reliability andmay operate more efficiently with very short transmission time intervals(TTIs). As one example, eMBB may require additional flexibility in theradio access technology, e.g., it may be desirable for the RAT to beapplications aware and be able to support a cloud based radio accessnetwork (RAN). To attain eMBB, it may also be desirable to increase thecapacity of current cellular networks through massive deployment ofsmall cells, high frequency reuse, and splitting of the Control and User(C/U) planes of the radio link. New RATs should also be sufficientlyflexible for future enhancements and support both licensed andunlicensed spectrum.

Cellular networks are currently used to support voice and datacommunications as well as various specific applications, such as sensornetwork monitoring, cloud capabilities, video streaming, automotivecommunications, real time gaming, remote control of devices,videoconferencing, and disaster alerts, among others. However, newercellular RATs should be sufficiently flexible to support futureapplications, such as autonomous driving, augmented reality, virtualreality, and tactile Internet, among numerous others.

Cellular Frame Structure Design in Future Cellular Networks

In some embodiments, different services such as MTC, eMBB, critical timeapplications, etc., utilize different transmit time interval (TTI)durations. MTC applications can have a longer TTI because of the natureof its power consumption. In contrast, eMBB and critical timeapplications may operate more efficiently with a shorter TTI.

Cellular transmissions should also be constrained in time and space toallow for coexistence with other technologies. In the current LTEstandard, the resource elements could be spread over 20 MHz and over a 1ms TTI. This results in reduced efficiency when the spectrum is sharedwith multiple services or use license assisted access (LAA) services.

Thus in some embodiments it may be desirable that radio resourcesallocated for control should be dynamic (non-static) to “fit” thedynamic TTI size of these different applications. In static TDD, thenetwork may define a 10 ms frame format where the transmission sequencemay be downlink, downlink, followed by uplink, uplink. In dynamic TDDthe TDD format can be changed, and further the TDD format used by twobase stations may be different. One problem with TDD is thattransmission and reception are performed at the same frequency. If twoneighboring base stations are operating where one is performingtransmission and one is performing reception, a mechanism is desired tohelp the base stations avoid interference. A dynamic TDD solution may beutilized to improve transmission quality and accommodate higherfrequencies. It is noted that an FDD solution may also be used forcertain markets

In some embodiments, cross layer communication may be introduced, suchas the provision of TCP/UDP and application type as part of thetransmission of TTI/resource size information. It would also bedesirable for the base station (eNB) to be able to configure device todevice (D2D) resources dynamically when two or more UEs are in range,enabling the two or more UEs to communicate directly with each other toreduce delay. Further, to avoid complexity when performing carrieraggregation, carriers may range from 10 to 200 MHz. Finally, it may bedesired to use the same TTI frame both in licensed and unlicensedspectrum.

FIG. 6—FDD Frame Structure

FIG. 6 illustrates a frame structure for frequency division duplexing(FDD) according to some embodiments, specifically a FDD self-containedframe with downlink/uplink scheduling. In FDD communications, differentfrequencies are defined for use in the downlink and the uplink. Asshown, one 10-100 MHz carrier component may be used for downlink, andone 10-100 MHz carrier component may be used for uplink. In the exampleshown in FIG. 6, after the pilot symbol is transmitted in the initial 10ms frame, control information in the control channel (PDCCH) (shaded)sent in the downlink carrier may indicate both where data resides in thedownlink and also where the UE is allowed to transmit HARQ feedback(ACK/NACK) in the uplink.

Header Layers

Each TTI data transmission sent over TCP or UDP may be encapsulated indifferent headers in 5G protocol stacks, and each transmission of thisencapsulated data over the physical layer is signaled using controlsignaling over the air (Radio Resources allocation). Typically, a datatransmission will include Layer 1 (L1) overhead that comprises controlsignaling for a dedicated or shared control channel, and Layer 2 (L2)overhead that includes a PDCP header, RLC header, MAC header, and CRC.Because the L1 and L2 overheads are of a fixed size per datatransmission, the ratio of L1+L2 overhead to data size will be inverselyproportional to the TTI. In other words, because the L1 and L2 overheadsrequire a fixed amount of time for transmission, a larger TTI results ina larger percent of the transmission time being dedicated to datatransmission. This improvement of data transmission efficiency for alonger TTI is generally desirable. However, if the end-to-end delay orthe round trip time (RTT) is more important than the overhead-to-dataratio for a particular data transmission, a shorter TTI may be desirablefor that transmission, in order to reduce the RTT.

Overview of the Fast Ramp Up Algorithm

The TCP congestion window represents the number of bytes that can beoutstanding at any time by a sender (the transmitting device), and hencerepresents the throughput of the sender. When a connection is set up, acongestion window may be maintained by the sender. In variousembodiments, the sender may be either of a user equipment (UE), or abase station (BS). For example, in the case of uplink communications,the UE may be the sender and the BS may be the receiver, while fordownlink communications, the BS may be the sender while the UE may bethe receiver. The congestion window may be used, in conjunction withother algorithms, to avoid sending more data than the network is capableof transmitting, i.e., to avoid causing network congestion. At leastsome embodiments described here may operate to increase the congestionwindow more rapidly and efficiently, thus achieving a higher, ormaximum, throughput more quickly than in prior systems.

In some embodiments, the congestion window is set initially to a smallmultiple of the Maximum Segment Size (MSS) allowed on that connection. Aslow start mechanism is used by the sender to determine the receiver'scongestion window. Upon completion of a data transmission, the sendermay receive a transmission control protocol acknowledgment (TCP-ACK)message from the receiver. Upon receipt of the TCP-ACK message, thesender may increase its congestion window for the subsequent datatransmission. For example, the sender may double its window on receiptof the ACK/NACK. This has the effect of increasing the sender'scongestion window each RTT. The congestion window may be iterativelyincreased for each data transmission until either: 1) a loss isdetected, or 2) the receiver's advertised window (rwnd) limits acongestion window increase, 3) a slow-start threshold (ssthresh) isreached, or 4) a timer is expired. If a loss event occurs, the algorithmassumes it is due to network congestion and takes steps to reduce theoffered load on the network.

Because the congestion window increases each RTT, and because decreasingthe TTI duration causes an effective decrease of the RTT, smaller TTIdurations will significantly reduce the amount of time required for thesender to ramp up to the maximum allowed congestion window. This fastramp up allows the UE or base station to reach a higher TCP throughputin a very short duration. For example, this fast ramp up allows the UEor base station to reach a maximum TCP throughput in a very shortduration.

FIG. 7—TCP Congestion Window Mechanisms

FIG. 7 is a chart which plots the sender's congestion window vs. timefor a typical execution of the slow-start algorithm. From the startuntil approximately t=5, the slow start algorithm quickly ramps up thecongestion window. At t=5, the congestion window reaches the ssthreshthreshold and begins a congestion avoidance phase that is marked by amore gradual, linear increase in the congestion window. Around t=13seconds, a congestion point is reached in the network and the sender'scongestion window is reset to the initial value at t=14. The slow startalgorithm is then implemented again, with a new, smaller value of thessthresh threshold.

The “slow start threshold” may be a preset threshold at which the UE orthe base station will discontinue using the shorter TTI and may beginusing a higher (or more normal) TTI. A benefit of the shorter TTIduration is that it allows a faster ramp up of the data throughput,e.g., it allows faster ramp up of the congestion window size, and henceallows faster increases in data throughput. A drawback of this shorterTTI duration is increased relative overhead. Since the amount of datatransmission overhead is fixed, the shorter TTI duration results in lessdata transfer per TTI, meaning that this fixed overhead is spread over asmaller amount of data, resulting a higher percentage of overhead peramount of data transferred. A benefit of the higher (or normal) TTIduration is that this fixed overhead is spread over a larger amount ofdata transferred, resulting in a lower percentage of overhead per amountof data transferred. Thus it is desirable to switch over from the lowTTI duration to the higher, or more normal, TTI duration at some point.

As shown in FIG. 7, the “slow start threshold” may be adjusted based onvarious criteria, e.g., if it has been determined that the ramp up ofthe congestion window in an earlier iteration may have been performedtoo quickly, resulting in network congestion, etc.

Relation Between TCP Window, Throughput TTI Duration, and Overhead

In order to benefit from both Congestion Window fast ramp and theimproved overhead for data transmission, the Downlink and Uplink TCPsessions may be configured to operate as follows:

When the TCP session begins, the UE may notify the base station that theTCP session has started. The base station (eNB) may then configure theUE with a small, preferably the smallest, transmit time interval (1 or 2symbol TTI) in order to reduce the TCP round trip time (RTT) (eventhough this results in a higher overhead). This may allow the TCPthroughput to ramp up faster to max throughput. When the TCP windowreaches its maximum value, the UE may notify the base station.Alternatively, the base station may use a timer to configure the UE witha longer TTI (14-16 symbol TTI) in order to improve the efficiency ofTCP and reduce the Layer 2/Layer 1 Overhead. For uplink transmission,the UE may notify the network also when it enters in Slow start modeduring the TCP session.

Uplink TCP Session

The following describes the uplink transmission operations by a UE and abase station. First, a TCP software stack in the UE may be configuredwith a maximum throughput value. The TCP software stack may execute inthe application processor of the UE. When the start of a new TCP sessionis detected, the UE's congestion window may be set to a minimum value,and the UE may check if the communication is through an enhancedcellular network, e.g., a 5G network. If so, a notification (an IPCmessage) may be sent to the 5G MAC software layer and the RRC softwarelayer in the UE. The MAC software layer in the UE may use thisinformation, in addition to other parameters such as targeted TCP maxthroughput, to send a MAC-CE or PHY message to the base stationrequesting a shorter TTI duration. The base station may then use thisinformation to configure the UE with a shorter TTI (1 or 2 OFDMsymbols). The base station may also configure the UE with contentionbased uplink resources in addition to a shorter TTI for this period.

The UE may proceed to communicate uplink data with the BS according tothe shorter TTI duration. The BS may be configured to transmit a TCP-ACKmessage to the UE upon receipt of each uplink data communication. The UEmay be configured to increase the congestion window upon receipt of eachTCP-ACK message. The TCP stack in the UE may continue monitoring theUE's congestion window state, and when a maximum or threshold value isreached for the congestion window, it may generate a new IPC message tothe UE MAC layer. The UE MAC layer may then the base station that theUE's congestion window has reached a maximum or threshold value and thatthe slow start is ending. At this point, the base station may switch theTTI scheduling for the UE to a normal TTI duration (14-16 OFDM symbols),which allows for a more efficient overhead-to-data ratio. If a slowstart is detected again during the TCP session, the UE may use the samemechanism to inform the base station, and the process is repeated.

FIG. 8—Uplink TCP Session, UE Architecture

FIG. 8 is a block diagram showing the components of an exemplary UE andbase station (eNB), overlaid with the steps involved in for theslow-start algorithm for an uplink TCP session. As shown, the system ofFIG. 9 includes a UE, a base station, and a network gateway coupled tothe base station. The UE may comprise various software layers, includingTCP and UDP layers, an IP layer, an RRC layer, a 5G PDCP (Packet DataConvergence Protocol) and NAS layer, a 5G RLC (Radio Link Control)layer, a 5G MAC (Media Access Control) layer, and an L1 or Phy layerwhich coupled to an RF front end. The base station may comprise a 5G MAClayer and a 5G Phy layer, among other possible layers.

At 1 the TCP layer in the UE notifies the 5G MAC layer in the UEregarding the beginning of the slow start.

At 2 the UE requests the base station to change the TTI scheduling to ashorter TTI duration for this bearer. More specifically, the 5G MAClayer in the UE may send a message to the 5G MAC layer in the basestation requesting the base station to change the TTI scheduling to ashorter TTI duration for this bearer.

At 3 the base station scheduler in the 5G layer requests the Phy portion(logic) to schedule the UE with a shorter transmit time interval (TTI)duration.

At step 4 the base station schedules the UE using the shorter TTI.

At step 5 the TCP layer in the UE notifies the 5G MAC layer that theslow start is ending.

At step 6 the UE requests the base station to change the TTI schedulingto a normal TTI duration.

Downlink TCP Session

The following describes the uplink transmission operations by a UE and abase station (BS). The downlink TCP method operates similarly to theuplink method, with several key differences. In a downlink TCP session,the TCP congestion window is maintained at a remote device or server,(e.g., at the BS in some embodiments) and the UE may have no exactknowledge of the sender's TCP window state. However, the UE does knowwhen the session starts and can measure the received throughput at anymoment. For a downlink TCP session, a generic slow start algorithm maybe employed, wherein, after initiating a TCP session with a remoteserver, the UE may send a notification to the base station in order toswitch to a shorter TTI duration. This may occur in a comparable mannerto that detailed for uplink transmission. In response to thenotification to switch to a shorter TTI duration, the BS may proceed tocommunicate downlink data with the UE according to the shorter TTIduration for a first period of time. The UE may be configured totransmit a TCP-ACK message to the BS upon each receipt of downlink datafrom the BS. The BS may be configured to increase the congestion windowupon each reception of a TCP-ACK message from the UE. In other words,the BS may be configured to increase a congestion window each round-triptime (RTT) for transmissions with the shorter TTI duration.

In some embodiments, when the notification is sent to the base station,a timer may be started. In these embodiments, upon completion of thetimer, the UE may send a notification to the base station to switch to anormal TTI duration, in a manner similar to that employed for an uplinksession. In an alternative embodiment, the timer could be maintained atthe base station. In other embodiments, the UE may send a notificationto the base station to switch to a normal TTI duration in response todetection, by the UE, of a packet loss in the downlink communications.In other embodiments, the base station may determine to switch to anormal TTI duration in response to detection, by the BS, of a packetloss in the downlink communication. In these embodiments, the BS maysend a notification to the UE of the switch to a normal TTI duration.

In some embodiments, either of the UE or the BS may be configured toinitiate the switch to a normal TTI duration based on the downlinktransmission rate reaching a slow start threshold. For example, in someembodiments the UE may send a notification to the base station to switchto a normal TTI duration in response to the downlink transmission ratereaching a slow start threshold. In other embodiments, the BS may switchto a normal TTI duration, and send a notification to the UE of theswitch, in response to the downlink transmission rate reaching a slowstart threshold.

FIG. 9—Downlink TCP Session, UE Architecture

FIG. 9 is a block diagram showing the components of an exemplary UE andbase station (eNB), overlaid with the steps involved in for theslow-start algorithm for a downlink TCP session. The various componentsand software layers in the UE and the base station may be similar tothat shown in FIG. 8.

At 1 the TCP layer in the UE notifies the 5G MAC layer in the UEregarding the beginning of the slow start and also starts a timer.

At 2 the UE requests the base station to change the TTI scheduling to ashorter TTI duration for this bearer. More specifically, the 5G MAClayer in the UE may send a message to the 5G MAC layer in the basestation requesting the base station to change the TTI scheduling to ashorter TTI duration for this bearer.

At 3 the base station scheduler in the 5G layer requests the Phy portion(logic) to schedule the UE with a shorter transmit time interval (TTI)duration.

At 4 the base station schedules the UE using the shorter TTI.

At 5 the timer expires and the TCP layer in the UE sends notification tothe base station to change to a normal TTI duration.

At 6 the UE requests the base station to change the TTI scheduling to anormal and more efficient TTI.

Some embodiments may be realized in any of the following forms:

In some embodiments, a wireless user equipment device (UE) may comprisea radio comprising one or more antennas configured for wirelesscommunication on a cellular network, and a processing element operablycoupled to the radio.

The UE may be configured to, prior to or during receipt of downlinkcommunication from a cellular base station in the cellular network,transmit a message to the base station requesting the base station tochange transmit time interval (TTI) scheduling to a shorter TTIduration.

The UE may be further configured to receive a message from the basestation indicating that the UE should use a shorter TTI duration,wherein the message is provided from the base station in response to themessage requesting the base station to change transmit time interval(TTI) scheduling to a shorter TTI duration.

The UE may be further configured to receive downlink communicationframes from the base station.

The UE may be further configured to transmit acknowledge messages to thebase station in response to receipt of each of the downlinkcommunication frames, wherein the acknowledge messages are sentaccording to the shorter TTI duration for a first period of time,wherein the acknowledge messages are further useable by the base stationto increase a congestion window during the first period of time.

The UE may be further configured to, after the first period of time,transmit a message to the base station requesting the base station tochange transmit time interval (TTI) scheduling to a normal TTI duration.

In some embodiments, a wireless user equipment device (UE) may comprisea radio comprising one or more antennas configured for wirelesscommunication on a cellular network, and a processing element operablycoupled to the radio.

The UE may be configured to, at or before start of an uplinkcommunication to a cellular base station in the cellular network,transmit a message to the base station requesting the base station tochange transmit time interval (TTI) scheduling to a shorter TTIduration.

The UE may be further configured to receive a message from the basestation indicating that the UE should use a shorter TTI duration,wherein the message is provided from the base station in response to themessage requesting the base station to change transmit time interval(TTI) scheduling to a shorter TTI duration.

The UE may be further configured to transmit uplink communications tothe base station according to the shorter TTI duration for a firstperiod of time, wherein the UE is configured to increase a congestionwindow size after each acknowledgement of an uplink communicationreceived by the base station.

The UE may be further configured to, after the first period of time,transmit a message to the base station requesting the base station tochange transmit time interval (TTI) scheduling to a second TTI duration,wherein the second TTI duration is longer than the shorter TTI duration.

In some of the previous embodiments, transmission of the uplinkcommunications to the base station according to the shorter TTI durationfor the first period of time may allow transmission control protocol(TCP) communications to ramp up to higher speeds more quickly than if anormal TTI duration was used during the first period of time.

In some of the previous embodiments, transmission of the uplinkcommunications to the base station according to the shorter TTI durationduring the first period of time may result in a shorter round trip time(RTT) than if a normal TTI duration was used during the first period oftime. In these embodiments, the UE may be further configured to increasea transmission rate after each uplink communication RTT.

In some of the previous embodiments, the first period of time ends inresponse to detection of a packet loss in the uplink communications.

In some of the previous embodiments, the first period of time ends inresponse to a threshold being reached.

In some of the previous embodiments, the congestion window size ismaintained and used by the UE to avoid transmitting a greater amount ofdata than can be handled by the network. In these embodiments, thecongestion window size may be increased after each round trip time,wherein increasing the congestion window size enables a correspondingincrease in uplink data throughput.

In some of the previous embodiments, the UE may be further configured toset the congestion window size initially to a small multiple of amaximum segment size (MSS) allowed on a connection between the UE andthe base station. In the embodiments, the UE may be further configuredto increase the congestion window size after each acknowledgement of anuplink communication received by the base station, thereby increasingthe congestion window size after each round trip time.

In some of the previous embodiments, the UE may be further configured totransmit the uplink communications to the base station according to thesecond TTI duration after the UE transmits the message to the basestation requesting the base station to change transmit time interval(TTI) scheduling to the second TTI duration.

Embodiments of the present disclosure may be realized in any of variousforms. For example, some embodiments may be realized as acomputer-implemented method, a computer-readable memory medium, or acomputer system. Other embodiments may be realized using one or morecustom-designed hardware devices such as ASICs. Still other embodimentsmay be realized using one or more programmable hardware elements such asFPGAs.

In some embodiments, a non-transitory computer-readable memory mediummay be configured so that it stores program instructions and/or data,where the program instructions, if executed by a computer system, causethe computer system to perform a method, e.g., any of a methodembodiments described herein, or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g., a UE 106) may be configured toinclude a processor (or a set of processors) and a memory medium, wherethe memory medium stores program instructions, where the processor isconfigured to read and execute the program instructions from the memorymedium, where the program instructions are executable to implement anyof the various method embodiments described herein (or, any combinationof the method embodiments described herein, or, any subset of any of themethod embodiments described herein, or, any combination of suchsubsets). The device may be realized in any of various forms.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. A wireless user equipment device (UE),comprising: a radio, comprising one or more antennas configured forwireless communication on a cellular network; a processing elementoperably coupled to the radio; wherein the UE is configured to: detectthat a transmission control protocol (TCP) session has been initiated;at least in part in response to detecting that the TCP session has beeninitiated, transmit a request to a base station for the base station tochange transmission time interval (TTI) scheduling to a first shorterTTI duration; in response to transmitting the request to the basestation to change TTI scheduling to the first shorter TTI duration,transmit first uplink communications to the base station according tothe first shorter TTI duration for a first period of time, wherein theUE is configured to increase a congestion window size after eachacknowledgement of a first uplink communication received by the basestation during the first period of time, wherein increasing thecongestion window size enables a corresponding increase in uplink datathroughput; after the first period of time, transmit a request to thebase station to change TTI scheduling to a second longer TTI duration;and in response to transmitting the request to the base station tochange TTI scheduling to the second longer TTI duration, transmit seconduplink communications to the base station according to the second longerTTI duration.
 2. The UE of claim 1, wherein transmission of the firstuplink communications to the base station according to the first shorterTTI duration during the first period of time results in a shorterround-trip time (RTT) than if the second longer TTI duration was usedduring the first period of time; wherein the UE is further configured toincrease a transmission rate after each first uplink communication RTTduring the first period of time.
 3. The UE of claim 1, wherein the firstperiod of time ends in response to detection of a packet loss in thefirst uplink communications.
 4. The UE of claim 1, wherein the firstperiod of time ends in response to a slow start threshold being reached.5. The UE of claim 1, wherein the first period of time ends in responseto the expiration of a timer.
 6. The UE of claim 1, wherein the UE isfurther configured to: set the congestion window size initially to asmall multiple of a maximum segment size (MSS) allowed on a connectionbetween the UE and the base station.
 7. The UE of claim 1, wherein theUE is further configured to: utilize contention based uplink resourcesallocated from the base station during the first period of time.
 8. TheUE of claim 1, wherein the UE is further configured to: in response todetecting that the TCP session has been initiated, notify a mediumaccess control (MAC) layer of the UE to initiate a slow start procedure;wherein said transmitting the request to the base station for the basestation to change TTI scheduling to the first shorter TTI duration isperformed by the MAC layer to initiate the slow start procedure.
 9. TheUE of claim 8, wherein said notifying the MAC layer of the UE toinitiate the slow start procedure is performed further in response to adetermination by the UE that the TCP session is through a 5^(th)Generation (5G) network.
 10. A method comprising: by a user equipmentdevice (UE): detecting that a transmission control protocol (TCP)session has been initiated; at least in part in response to detectingthat the TCP session has been initiated, transmitting a request to abase station for the base station to change transmission time interval(TTI) scheduling to a first shorter TTI duration; in response totransmitting the request to the base station to change TTI scheduling tothe first shorter TTI duration, transmitting first uplink communicationsto the base station according to the first shorter TTI duration for afirst period of time, wherein the UE is configured to increase acongestion window size after each acknowledgement of a first uplinkcommunication received by the base station during the first period oftime, wherein increasing the congestion window size enables acorresponding increase in uplink data throughput; after the first periodof time, transmitting a request to the base station to change TTIscheduling to a second longer TTI duration; and in response totransmitting the request to the base station to change TTI scheduling tothe second longer TTI duration, transmitting second uplinkcommunications to the base station according to the second longer TTIduration.
 11. The method of claim 10, wherein transmission of the firstuplink communications to the base station according to the first shorterTTI duration during the first period of time results in a shorterround-trip time (RTT) than if the second longer TTI duration was usedduring the first period of time; wherein the method further comprisesincreasing a transmission rate after each first uplink communication RTTduring the first period of time.
 12. The method of claim 10, wherein thefirst period of time ends in response to one of: detection of a packetloss in the first uplink communications; a slow start threshold beingreached; or expiration of a timer.
 13. The method of claim 10, themethod further comprising: setting the congestion window size initiallyto a small multiple of a maximum segment size (MSS) allowed on aconnection between the UE and the base station.
 14. The method of claim10, the method further comprising: by the base station, configuring theUE with contention based uplink resources during the first period oftime.
 15. The method of claim 10, the method further comprising: inresponse to detecting that the TCP session has been initiated, notifyinga medium access control (MAC) layer of the UE to initiate a slow startprocedure; wherein said transmitting the request to the base station forthe base station to change TTI scheduling to the first shorter TTIduration is performed by the MAC layer to initiate the slow startprocedure.
 16. The method of claim 15, wherein said notifying the MAClayer of the UE to initiate the slow start procedure is performedfurther in response to a determination by the UE that the TCP session isthrough a 5^(th) Generation (5G) network.
 17. An apparatus configuredfor implementation within a user equipment (UE), comprising: one or moreprocessing elements configured to cause the UE to: detect that atransmission control protocol (TCP) session has been initiated; at leastin part in response to detecting that the TCP session has beeninitiated, transmit a request to a base station for the base station tochange transmission time interval (TTI) scheduling to a first shorterTTI duration; in response to transmitting the request to the basestation to change TTI scheduling to the first shorter TTI duration,transmit first uplink communications to the base station according tothe first shorter TTI duration for a first period of time, wherein theUE is configured to increase a congestion window size after eachacknowledgement of a first uplink communication received by the basestation during the first period of time, wherein increasing thecongestion window size enables a corresponding increase in uplink datathroughput; after the first period of time, transmit a request to thebase station to change TTI scheduling to a second longer TTI duration;and in response to transmitting the request to the base station tochange TTI scheduling to the second longer TTI duration, transmit seconduplink communications to the base station according to the second longerTTI duration.
 18. The apparatus of claim 17, wherein the first period oftime ends in response to one of: detection of a packet loss in the firstuplink communications; a slow start threshold being reached; orexpiration of a timer.
 19. The apparatus of claim 17, wherein the one ormore processing elements are further configured to cause the UE to: inresponse to detecting that the TCP session has been initiated, notify amedium access control (MAC) layer of the UE to initiate a slow startprocedure; wherein said transmitting the request to the base station forthe base station to change TTI scheduling to the first shorter TTIduration is performed by the MAC layer to initiate the slow startprocedure.
 20. The apparatus of claim 19, wherein said notifying the MAClayer of the UE to initiate the slow start procedure is performedfurther in response to a determination by the UE that the TCP session isthrough a 5^(th) Generation (5G) network.